数値計算による自己誘起磁場型アルゴンMPDスラスタの熱設計

Abstract

A 400-kW-class steady-state self-field magnetoplasmadynamic (MPD) thruster is numerically designed with a combination of magnetohydrodynamic (MHD) and thermal analyses, where a heat flux evaluated from the MHD analysis is imposed on the electrode as a boundary condition in the thermal analysis. The increase in the ratio of an anode radius to a cathode radius improves the thrust performance, but can rise the temperature locally at an anode downstream edge and a cathode tip due to the concentration of discharge current and/or insufficient heat removal. It is suggested, however, that a thruster without electrode melting is realizable even at such a high input power by setting an appropriate cathode radius and enhancing heat removal from the electrode by means of heat pipe. The thruster designed under the thermal constraint is expected to achieve a thrust of 17 N, a specific impulse of 990s, a thrust efficiency of 21% for argon propellant.